If a defendant testifies, can they bring in a witness to support their truthfulness?

When a defendant testifies in court, they have the right to present evidence that supports their credibility or truthfulness as a witness. However, they cannot simply introduce character witnesses to bolster their truthfulness without first having their credibility challenged.

In most jurisdictions, the law recognizes that the defendant's testimony may be scrutinized, and if their honesty or truthfulness comes into question during the trial (for example, through cross-examination or opposing evidence), that is when the defendant may then introduce supporting witnesses to affirm their character for truthfulness. This approach preserves the integrity of the trial process by ensuring that character evidence is only brought in to counteract specific allegations about dishonesty that have been raised, rather than allowing it to serve as a blanket endorsement of the defendant’s credibility without basis.

Thus, the requirement that a defendant's truthfulness must first be questioned before they can bring in character witnesses to support their credibility is crucial for maintaining the due process rights of both the defendant and the integrity of the judicial system.